Computer aided diagnosis apparatus and method based on size model of region of interest

ABSTRACT

A Computer Aided Diagnosis (CAD) apparatus and CAD method for detection of ROIs based on an ROI size transition model. The CAD apparatus includes: an image receiver configured to sequentially receive images; a region of interest (ROI) acquirer configured to acquire an ROI from a current image based on an ROI size transition model; and an ROI output configured to output visual information indicating the acquired ROI.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority from Korean Patent Application No.10-2014-0122908, filed on Sep. 16, 2014, in the Korean IntellectualProperty Office, the entire disclosure of which is incorporated hereinby reference for all purposes.

BACKGROUND

1. Field

The following description relates to a Computer Aided Diagnosis (CAD)apparatus and method for supporting detection and display of a region ofinterest based on a region of interest (ROI) size transition model.

2. Description of Related Art

In the medical diagnosis field, ultrasound images are used to diagnosepatients' conditions. Medical practitioners generally apply a probe to apatient's body parts to acquire ultrasound images in real time, checkthe acquired ultrasound images output to a screen with the naked eye,detect and determine a lesion or a suspected region. If there is aregion suspected to include a lesion, medical practitioners move theprobe slowly or stop the probe to observe the suspected region.

The computer aided diagnosis (CAD) system analyzes various medicalimages to detect lesions, and determines whether detected lesions arebenign or malignant to provide the diagnosis results to medicalpractitioners. In a general CAD system, ultrasound imaging diagnosis isperformed such that a lesion is first identified using ultrasound, andthen is determined by a separate CAD system. Research on the real-timeCAD system is currently being conducted where a lesion is detected fromultrasound images acquired in real time to diagnose the lesion.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, there is provided a Computer Aided Diagnosis(CAD) apparatus, including an image receiver configured to sequentiallyreceive images, a region of interest (ROI) acquirer configured toacquire an ROI from a current image based on an ROI size transitionmodel, and an ROI output configured to output visual informationindicating the acquired ROI.

The image receiver may receive in real time ultrasound images acquiredthrough a probe in units of frames.

The ROI acquirer may include an ROI detector configured to detect one ormore ROIs from the current image.

The ROI acquirer may further include an ROI determiner configured todetermine whether a ROI from the one or more detected ROIs iserroneously detected based on the ROI size transition model.

The determiner may be configured to determine a size state of thedetected ROI by matching the size of the detected ROI with the ROI sizetransition model, and determine that the detected ROI is erroneouslydetected, in response to determining that a size state of a previousimage on the ROI size transition model is not capable of beingtransformed to the determined size state of the current image.

In response to the detected ROI being erroneously detected, the ROIoutput component may be further configured to not output visualinformation on the detected ROI.

In response to the detected ROI being erroneously detected, the ROIoutput component may be further configured to determine the biggest sizestate that is possible to transition from the size state of the previousimage using the ROI size transition model, and to output visualinformation on the detected ROI that has a size corresponding to thebiggest size state.

The ROI acquirer may further include an ROI predictor configured topredict an ROI in the current image using the ROI size transition model,in response to the ROI not being detected from the current image.

The ROI predictor may determine a size state transitionable from thesize state of the ROI acquired from the image before the current imageusing the ROI size transition model, and to predict the ROI in thecurrent image using the determined size state.

The ROI size transition model may be created using the Markov modellearning based on a change in sizes of ROIs in a sequence of images foreach interested item, and the ROI size transition model comprises sizestates, a transition possibility between the size states, transitiondirection, and transition probability information.

In order to indicate a location and size of the ROI in the current imagethat is output on the screen, the visual information may include firstinformation comprising at least one of square, round, oval, or crossshapes, and second information comprising at least one of color, typesof lines, or thickness of lines of the first information.

The visual information may be output on a screen.

The ROI acquirer may be configured to detect the one or more ROIs basedon geo-spatial location information of the one or more ROIs.

In another general aspect, there is provided a Computer Aided Diagnosis(CAD) method, including: sequentially receiving images; acquiring aregion of interest (ROI), at a processor, from a current image based onan ROI size transition model, and outputting visual information thatindicates the acquired ROI.

The acquiring of the ROI may include detecting one or more ROI from thecurrent image.

The acquiring of the ROI may include, determining whether a ROI from theone or more detected ROI is erroneously detected based on the ROI sizetransition model.

The determining of the ROI may include determining a size state of thedetected ROI by matching the size of the detected ROI with the ROI sizetransition model, and determining that the detected ROI is erroneouslydetected, in response to determining that a size state of a previousimage on the ROI size transition model is not capable of beingtransformed to the determined size state of the current image.

The outputting of the ROI may include, in response to the detected ROIbeing erroneously detected, the outputting of the ROI comprises notoutputting visual information on the detected ROI.

In response to the detected ROI being erroneously detected, theoutputting of the ROI may include determining the biggest size statethat is possible to transition from the size state of the previous imageusing the ROI size transition model, and outputting visual informationon the detected ROI that has a size corresponding to the biggest sizestate.

The acquiring of the ROI may include predicting an ROI in the currentimage using the ROI size transition model in response to the ROI notbeing detected from the current image.

The predicting of the ROI may include determining a size statetransitionable from the size state of the ROI acquired from the imagebefore the current image using the ROI size transition model, andpredicting the ROI in the current image using the determined size state.

The ROI size transition model may be created using the Markov modellearning based on a change in sizes of ROIs in a sequence of images foreach interested item, and the ROI size transition model may include sizestates, a transition possibility between the size states, transitiondirection and transition probability information.

In another general aspect, there is provided a Computer Aided Diagnosis(CAD) apparatus, including an image receiver configured to sequentiallyreceive images, a region of interest (ROI) acquirer configured toacquire one or more ROIs from a current image based on an ROI sizetransition model, and a model builder configured to extract modelinformation from the received images and the one or more ROIs.

The model information may include at least one of a size of a ROI visualinformation from the one or more detected ROIs, the shape of the ROIvisual information, the geo-spatial location of the ROI visualinformation, or a number of pixels.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a Computer-AidedDiagnosis (CAD) apparatus.

FIG. 2 is a diagram illustrating an example of the ROI acquirer of FIG.1.

FIG. 3 is a diagram illustrating an example of an ROI in a sequence ofimages.

FIG. 4 is a diagram illustrating an example of a Computer-AidedDiagnosis (CAD) apparatus.

FIGS. 5A to 5C are diagrams illustrating examples of an ROI sizetransition model.

FIGS. 6A and 6B are diagrams illustrating examples of acquiring andoutputting of an ROI.

FIGS. 7A and 7B are diagrams illustrating examples of acquiring andoutputting of an ROI.

FIG. 8 is a diagram illustrating an example of a Computer-AidedDiagnosis (CAD) method.

FIG. 9 is a diagram illustrating an example of acquiring of an ROI.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the systems, apparatuses, and/ormethods described herein will be apparent to one of ordinary skill inthe art. The progression of processing steps and/or operations describedis an example; however, the sequence of and/or operations is not limitedto that set forth herein and may be changed as is known in the art, withthe exception of steps and/or operations necessarily occurring in acertain order. Also, descriptions of functions and constructions thatare well known to one of ordinary skill in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided so thatthis disclosure will be thorough and complete, and will convey the fullscope of the disclosure to one of ordinary skill in the art.

FIG. 1 is a diagram illustrating an example of a Computer-AidedDiagnosis (CAD) apparatus.

The CAD apparatus 100 analyzes ultrasound images acquired in real timethrough a probe to detect and classify regions of interest (ROIs).However, the CAD apparatus 100 is not limited thereto, and may includean apparatus that receives a sequence of images acquired in real time ora sequence of pre-acquired images using various image capturing devicesto detect and classify ROIs. Referring to FIG. 1, the CAD apparatus 100includes an image receiver 110, an ROI acquirer 120, and an ROI outputcomponent 130.

The image receiver 110 sequentially receives images, where the imagesmay be successively captured medical images of examined regions of asubject. For example, a user that performs examination applies a probeto a diseased area, such as, for example, lesion, fingers, toes,abdomen, breast, and chest of a subject and moves the probe around thearea to acquire images. The image receiver 110 may receive the images inreal time. Images may be transmitted in units of frames in real time,and the image receiver 110 transmits the images received in real time tothe ROI detector 120 for processing. The ROI detector 120 may acquire anROI from a current image every time an image is received. The ROI refersto a region that includes items of interest for the purposes ofdiagnosis, such as, for example, lesion, fingers, toes, abdomen, breast,and chest. The ROI detector 120 may acquire an ROI from a current imagebased on an ROI size transition model. The ROI size transition model maybe created in advance based on a change in sizes of ROIs in a sequenceof images for each ROI. The above-described creation of the ROI sizetransition model is a non-exhaustive example, and other methods ofcreating the ROI size transition model are considered to be well withinthe scope of the present disclosure. For example, the size model may becreated by a user without learning. In another example, the ROI sizetransition model may be created by learning, or may be a Markov modelthat is created in the form of rules. The ROI size transition model mayinclude size states, transition possibility between the size states, atransition direction, and transition probability information, which willbe described in further detail with reference to FIG. 4.

In one example, the ROI acquirer 120 may acquire an ROI using anautomatic detection algorithm. Upon detecting an ROI, an ROI sizetransition model may be used to determine whether the ROI is erroneouslydetected.

In another example, where an ROI is not detected from a current imageusing an automatic detection algorithm, an ROI may be predicted in thecurrent image based on information on an ROI tracked in a previous imageand an ROI size transition model.

The ROI output component 130 outputs an ROI detected by the ROI acquirer120 to be displayed on a screen. Based on the location and size of thedetected ROI, the ROI output component 130 may output an ROI for displayon a screen by outputting visual information associated with the ROI ata position that corresponds to a current image output to a screen. Inorder to display the size and location of an ROI, the visual informationmay include first information regarding shapes, such as, for example,square, round, oval, and cross. The visual information may also includeinformation regarding color, types and thickness of lines, and the like.

In one example, if the ROI acquirer 120 determines that an automaticallydetected ROI is erroneously detected, the ROI output component 130 maynot output visual information on the ROI.

In another example, if an ROI detected from a current image is an ROIthat has been tracked from a previous image, and the ROI is determinedto be detected erroneously, the ROI output component 140 may determinethe size state of the ROI appropriate for a current image using an ROIsize transition model, and may output on a screen visual informationhaving a size corresponding to the determined size state. In this case,a maximum possible size state that may be transitioned from the sizestate of an ROI detected from a previous image may be determined to be asize state appropriate for a current image.

It may be predetermined by a user whether to output an ROI that iserroneously detected from a current image. For example, in such a casevisual information may not be output for an ROI that is newly detectedfrom a current image, and visual information may be output for an ROIthat has been tracked from a previous image.

FIG. 2 is a diagram illustrating an example of a ROI acquirer of FIG. 1.Referring to FIG. 2, the ROI acquirer 120 includes an ROI detector 121,an ROI determiner 122, and an ROI predictor 123.

The ROI detector 121 may detect an interested item by applying andetection algorithm of an ROI to a received current image, and maydetermine a region that includes the interested item to be an ROI.Examples of the ROI detection algorithm may include algorithms such as,for example, AdaBoost, Deformable Part Models (DPM), Deep Neural Network(DNN), Convolutional Neural Network (CNN), Sparse Coding. Thealgorithm(s) to be applied may be determined depending on factors suchas, for example, the performance of the apparatus 100, diagnosispurposes, and diagnosis time.

Once an ROI is detected from a current image, the ROI determiner 122 maytrack the ROI, and determine whether the ROI is identical to an ROI thathas been detected from a previous image. In one example, usinggeo-spatial location information of the detected ROI, the location ofthe ROI is compared to a location of an ROI detected from a previousimage to determine whether the two regions of interest are identical. Inanother example, it may be determined whether the detected ROI and anROI that has been tracked are identical to each other using techniquessuch as, for example, Jaccard similarity algorithm, and Mean shiftalgorithm.

FIG. 3 is a diagram illustrating an example of an ROI in a sequence ofimages. As illustrated in FIG. 3, an item of interest, such as a lesion,is generally three-dimensional. The size of an three-dimensional ROI isgradually increases from a point in time (t−2) when the ROI is initiallydetected to a point in time (t+3) when the ROI is lastly detected, andthen the size decreases. Referring to FIG. 3, the ROI is small at (t−2)when it is initially detected, and then is gradually increased to amaximum size at a current time (t). The size of the detected ROIgradually decreased after the points in time t+1 to t+3.

As illustrated in FIG. 3, once an ROI is detected from a current image,the ROI determiner 122 may determine whether the detected ROI iserroneously detected based on a change in size of an ROI.

For example, assuming that no ROI is detected from an image at aprevious time t−1, if an ROI having a size as illustrated in FIG. 3 isdetected for the first time from an image of a current time (t), the ROIdeterminer 122 may determine that the ROI is erroneously detected. Wherean ROI, as illustrated in FIG. 3, is detected for the first time, an ROIhaving a size corresponding to the size of an ROI detected at a point intime t−2 is normally detected, with no possibility of suddenly detectingan ROI having a size bigger than the size, such that it is determinedthat the ROI is erroneously detected. In another example, while an ROIhas been tracked in previous images during points in time (t−2, . . . ,and t−1), if an ROI having a size that is not normal in an image of acurrent time (t), e.g. a size that is not possible to be detectedimmediately after a size of an ROI detected from a previous image att−1, the detected ROI may be determined to be erroneously detected.

The ROI determiner 122 may determine the size state of a detected ROI bymatching the size of an ROI detected from a current image with an ROIsize transition model. Once the size state is determined, it isdetermined whether it is possible to transition from the size state ofan ROI detected from a previous image, and based on the determination,it may be determined whether an ROI is erroneously detected.

If an ROI is not automatically detected from a current image, the ROIpredictor 123 may predict an ROI that is appropriate for a current imageusing an ROI size transition model. In general, an ROI, which has beentracked from a previous image, does not suddenly disappear at a certainpoint. Where an ROI, which has been tracked from a previous image,disappears suddenly from a current image, the ROI predictor 123 maydetermine that an ROI, which is to be detected, is not detected, and maypredict an ROI having a size appropriate to be detected from a currentimage.

For example, the ROI predictor 123 may identify a change in size usingROI tracking information in previous images, i.e., using information onthe size of an ROI acquired from a previous image, and may determine asize state that is likely to be detected from a current image on an ROIsize transition model. Further, using ROI location information of aprevious image, the ROI predictor 123 may determine the location of anROI in a current image.

FIG. 4 is a diagram illustrating an example of a Computer-AidedDiagnosis (CAD) apparatus according to another example. Referring toFIG. 4, the Computer Aided Diagnosis (CAD) apparatus 300 includes animage receiver 310, an ROI acquirer 320, an ROI output component 330,and a model builder 340. The above descriptions of FIGS. 1-3 is alsoapplicable to the image receiver 310, the ROI acquirer 320, and the ROIoutput component 330 shown in FIG. 4, and is incorporated herein byreference. Thus, the above description may not be repeated here.

The model builder 340 may build an ROI size transition model based onthe change in size of an ROI desired by a user in a sequence ofcollected images.

The model builder 340 may collect a sequence of 3D video datasuccessively captured to acquire an ROI, or video data acquired in realtime, and may extract ground truth from the collected data to build anROI size transition model. The ground truth may include information,such as, for example, the size of an ROI visual information, the shapeof an ROI visual information (such as, for example, a square shape, anoval shape, a round shape, a cross mark), and a number of pixels.

The model builder 340 may generate an ROI size transition model by amethodology such as, for example, the Markov Model learning based on theextracted ground truth. Further, in the case where a user is well awareof the change in size of an ROI through specialized knowledge, diagnosisexperiences, or the like, an ROI size transition model may be directlygenerated by the user without specific learning.

FIGS. 5A to 5C are diagrams explaining an ROI size transition modelaccording to an example. Referring to FIGS. 4, 5A, and 5B, the modelbuilder 340 may generate a size transition model that includesinformation such as, for example, size states (0, 1, 2, . . . , n-1, andn), probability of transition between the size states (0, 1, 2, . . . ,n-1, and n), and transition probability information as illustrated inFIG. 5A, in which size state 0 denotes a state where an ROI is notdetected, size state 1 denotes the smallest size of an ROI, and sizestate n denotes the largest size of an ROI.

As illustrated in FIG. 5B, assuming that four successive image framesf104, f105, f106, and f107 include ROIs 51, 52, 53, and 54,respectively, and the sizes of the ROIs increase in order from 51 to 54.The model builder 340 may define, as states 1, 2, 3, and 4, the sizes ofthe ROIs 51, 52, 53, and 54 detected from each of the four successiveimage frames f104, f105, f106, and f107.

The model builder 340 may calculate probability of transition betweeneach state using Equation 1, and the calculated probability oftransition between each state is illustrated in FIG. 5C. For example, ifa current n-1 frame has state 1 (e.g., 10 mm² in size), and the size ofan ROI detected from the n frame is 12 mm², the transition from state 1to state 2 may be calculated to have the highest probability asillustrated in FIG. 5C.

P(B _(n,m) |B _(n31 1,m) , B _(n−2,m)) ∝P(S _(n,m) |S _(n−1,m) , S_(n−2,m))·f(D _(B) _(m) ) [Equation 1]

Here, B represents the size of a detected ROI, S represents a size stateof the ROI, D represents a detection score of the ROI, n denotes framen, and m denotes an index of the ROI interest detected from frame n. Forexample, B_(n,m) denotes an m^(th) ROI detected from frame n.

FIGS. 6A and 6B are diagrams explaining acquiring and outputting of anROI according to an example. FIGS. 7A and 7B are diagrams explainingacquiring and outputting of an ROI according to another example.

FIGS. 6A to 7B illustrate examples of acquiring and outputting an ROI bythe Computer Aided Diagnosis (CAD) apparatuses 100 and 300 illustratedin FIGS. 1 and 4. For convenience of explanation, FIGS. 6A to 7B will bedescribed with reference to the CAD apparatus 100 illustrated in FIG. 1,and with reference to an ROI size transition model illustrated in FIG.5A.

FIG. 6A is a diagram explaining an abnormally big ROI 62 detected from acurrent frame f105. The size of an ROI detected from a previous framef104 corresponds to state 1 in an ROI size transition model, and thesize of the ROI 62 detected from the current frame f105 corresponds tostate 5.

Once the image receiver 110 receives the current frame f105, the ROIacquirer 120 may detect the ROI 62 using an automatic detectionalgorithm as described above.

Once the ROI 62 is detected from the current frame f105, the ROIacquirer 120 may perform matching by comparing the ROI 61 of theprevious frame f104 to the ROI 62 of the current frame f105 in terms ofa geo-spatial location and using Jaccard similarity. If the ROI 61 ofthe previous frame f104 is matched with the ROI 62 of the current framef105, it is determined to be a normal detection. If they are not matchedwith each other, the size of the ROI 61 is further matched with an ROIsize transition model to determine whether it is an erroneous detection.

If the ROI 61 of the previous frame f104 is not matched with the ROI 62of the current frame f105, the ROI acquirer 120 matches the size of theROI 62 with an ROI size transition model, and determines the size of theROI 62 to be equivalent to that of state 5. Since the size of an ROI maynot transition from state 1 to state 5, it may be determined to be anerroneous detection.

The ROI output component 130 determines state 3 to be the biggestpossible state to which state 1 of the ROI 61 of the previous frame f104may transition, and outputs visual information with a size correspondingto the determined size state 3 on a screen to display the ROI 63 of thecurrent image.

FIG. 6B is a diagram explaining three ROIs 65, 66, and 67 detected fromthe current frame f107, in which it is assumed that the size of the ROI64 detected from the previous frame f106 is 10 mm, and the size is state1 in an ROI size transition model.

Once three ROIs 65, 66, and 67 are detected from the current frame f107,the ROI acquirer 120 matches each of the ROIs 65, 66, and 67 with theROI 64 in the previous frame f106, in which the matching may beperformed in terms of a geo-spatial location and using Jaccardsimilarity.

Once the first ROI 65 of the current frame f107, which is 12 mm in size,is matched with the ROI 64 of the previous frame f106, the ROI acquirer120 may determine that it is a normal ROI that has been continuouslytracked from a previous image, without need for an ROI size transitionmodel.

In this case, the ROI output component 120 may output visual informationthat includes the detected ROI 65 having a size of 12 mm on a screen todisplay the ROI 65.

Further, the second and third ROIs 66 and 67 detected from the currentframe f107 are new ROIs that have not been detected from the previousframe f106, and thus, are not matched with the previous frame f106. Inthis case, the ROI acquirer 120 may determine whether the ROIs 66 and 67are erroneously detected using an ROI size transition model.

In one example, the ROI acquirer 120 may calculate a probability ofdetecting the ROIs 66 and 67 for the first time, and may determine thatthe ROIs 66 and 67 are erroneously detected if the calculated detectionprobability is below a threshold.

In this case, the detection probability may be calculated by consideringdetection scores calculated when ROIs are detected using an automaticdetection algorithm, and considering transition probability on an ROIsize transition model, in which the detection probability may becalculated by an equation of detection score times transitionprobability.

For example, if a detection score of the second ROI 66 is 10, and thesize on an ROI size transition model is state 2, probability oftransition from state 0 where no ROI is detected from a previous imageto state 2 is 0.05, with detection probability of 0.5 (0.05×10).Similarly, if a detection score of the third ROI 67 is 25, and the sizeis state 1, probability of transition from state 0 to state 1 is 0.5,with detection probability of 12.5 (0.5×25). If a predeterminedthreshold is 10, the second ROI 66 is below the threshold, and thus isdetermined to be erroneously detected.

As the second ROI 66 is determined to be erroneously detected, the ROIoutput component 130 does not output visual information for displayingthe ROI 66. Further, as the ROI 67 is determined to be detectednormally, visual information for displaying the ROI 67 is output. InFIG. 6B, the ROI 66 is shown in a box indicated with “X”, which meansvisual information for the ROI 66 is not output.

FIGS. 7A and 7B are diagrams explaining examples for acquiring andoutputting of an ROI according to another example.

FIG. 7A illustrates that with respect to five sequentially input framesf107, f108, f109, f110, and f111;, ROIs 71, 72, 73, and 74 which havebeen detected and tracked from the previous frames f107, f108, f109, andf110 respectively, are not detected from the current frame f111 using anautomatic detection algorithm.

If a desired ROI 75 is not detected from the current frame f111 using anautomatic detection algorithm, the ROI acquirer 120 may predict an ROIusing various types of information calculated by an automatic detectionalgorithm, e.g., information on candidate regions, detection scores ofeach of the candidate regions, transition probability for each of thecandidate regions, sizes and locations of the ROIs 71, 72, 73, and 74detected from the previous frames f107, f108, f109, and f110, and thelike, so that the ROI 75 may be detected.

For example, if the size of the ROI 74 detected from the previous framef110 is state 1, the state may transition to any one state of 0, 1, or 2on an ROI size transition model. In this case, if an ROI, which has beentracked, is not detected from the current frame f111, the ROI acquirer120 determines whether the size of the ROI normally transitions from 1to 0.

As shown in the frame f111 illustrated in the middle of FIG. 7B, the ROIacquirer 120 may select neighboring candidate regions, which arepositioned within a predetermined threshold from the center of the ROI74 of the previous frame f110, from among candidate regions of thecurrent frame f111 calculated using an automatic detection algorithm,and using detection scores and sizes of the selected candidate regions,the ROI acquirer 120 may predict the ROI 75.

Referring to FIG. 7B, it may be understood that two candidate regions ofstate 1 and four candidate regions of state 2 are selected from amongcandidate regions of states 0, 1, and 2 that may transition from the ROI74 of the previous frame f110. The ROI acquirer 120 may predict, as theROI 75, a region with the highest detection probability (e.g., detectionscore x transition probability) among the selected candidate regions.

Once the ROI 75 is predicted, the ROI output component 130 may outputvisual information having a size corresponding to the size of the ROI 75to display the ROI.

FIGS. 8 and 9 are diagrams illustrating examples of a Computer-AidedDiagnosis (CAD) method. FIG. 9 is a diagram illustrating a method ofacquiring an ROI. The operations in FIGS. 8-9 may be performed in thesequence and manner as shown, although the order of some operations maybe changed or some of the operations omitted without departing from thespirit and scope of the illustrative examples described. Many of theoperations shown in FIGS. 8-9 may be performed in parallel orconcurrently. The above description of FIGS. 1-7B, is also applicable toFIGS. 8-94, and is incorporated herein by reference. Thus, the abovedescription may not be repeated here.

Examples illustrated in FIGS. 8 and 9 may be performed by the ComputerAided Apparatuses (CAD) 100 and 300 illustrated in FIGS. 1 and 4.

Referring to FIG. 8, in 510, the CAD apparatus sequentially receivesimages, in which the received images may be ultrasound images acquiredthrough a probe, and may be received in units of frames in real time.

In 520, an ROI is acquired from the received images. The ROI may beacquired using a pre-stored ROI size transition model.

The acquisition of an ROI in 520 may be described in further detail byreferring to FIG. 9. In 611, the CAD apparatus detects an ROI from acurrent image using a pre-stored automatic detection algorithm. Once anROI desired by a user is detected, in 612, the detected ROI is matchedwith an ROI detected from a previous image by comparing the ROIs interms of geo-spatial locations or using Jaccard similarity algorithm. Ifthe ROIs are matched, the detected ROI is determined to be a normal ROIand is output in 619.

If the ROIs are not matched, in 613, the size state of the detected ROIis determined based on a pre-stored ROI size transition model. In 614,it is determined whether the determined size state is appropriate. Forexample, the size state of an ROI detected from a current image may bematched with the size state of an ROI detected from a previous image ofan ROI size transition model. Based on this comparison, it may bedetermined whether the size state of an ROI detected from a currentimage could possibly have transitioned from the size state of an ROIdetected from the previous image. Based on the comparison, it may bedetermined whether the determined size state is appropriate.

If it is determined in 614 that the size state of a detected ROI isappropriate, the detected ROI is output in 619.

If it is determined in 614 that the size state of a detected ROI couldnot have transitioned from the size state of an ROI of a previous image,in 615, it is determined that the ROI is erroneously detected.

In 616, it may be determined whether to output the ROI that has beendetermined to be erroneously detected. It may be predetermined whetheror not to output an erroneously detected ROI. For example, an ROI, whichhas been tracked from a previous image, may be output in a currentimage, and if a newly-detected ROI from the current image is erroneouslydetected, the ROI may not be output.

In 616, if it is determined to output an erroneously detected ROI, thesize state appropriate for a detected ROI may be determined in 617 basedon an ROI size transition model. An ROI having a size corresponding tothe determined size state may be output in 619. For example, if the sizestate of an ROI detected from a current image may not transition from asize state of an ROI detected from a previous image, the biggestpossible size state that may transition from the size state of the ROIof a previous image may be determined to be the size state that may beoutput.

If an ROI is not detected using an automatic detection algorithm in 612,an ROI that is appropriate for a current image may be predicted in 618using a pre-stored ROI size transition model. As described above,detection probability may be calculated using detection scores andtransition probabilities of candidate regions, which are positionedwithin a predetermined threshold from the center of the ROI detectedfrom the previous image frame using an automatic detection algorithm. Acandidate region having the highest detection probability may bepredicted as an ROI of a current image.

Referring back to FIG. 8, in 530, once an ROI is acquired from a currentimage, visual information is output, which may be output on a screen toinform a user of the ROI. Among ROIs automatically detected in 520,visual information on an ROI, which has been determined to beerroneously detected, may not be output. In another example, if an ROIis a region that has been tracked from a previous image, the size of thedetected ROI is matched with an ROI size transition model, so thatvisual information having a size corresponding to a maximum possiblesize that may transition from the size of an ROI of a previous image maybe output.

The apparatuses, units, modules, devices, and other componentsillustrated that perform the operations described herein are implementedby hardware components. Examples of hardware components includecontrollers, sensors, generators, drivers and any other electroniccomponents known to one of ordinary skill in the art. In one example,the hardware components are implemented by one or more processors orcomputers. A processor or computer is implemented by one or moreprocessing elements, such as an array of logic gates, a controller andan arithmetic logic unit, a digital signal processor, a microcomputer, aprogrammable logic controller, a field-programmable gate array (FPGA), aprogrammable logic array, a microprocessor, an application-specificintegrated circuit (ASIC), or any other device or combination of devicesknown to one of ordinary skill in the art that is capable of respondingto and executing instructions in a defined manner to achieve a desiredresult. In one example, a processor or computer includes, or isconnected to, one or more memories storing instructions or software thatare executed by the processor or computer. Hardware componentsimplemented by a processor or computer execute instructions or software,such as an operating system (OS) and one or more software applicationsthat run on the OS, to perform the operations described herein. Thehardware components also access, manipulate, process, create, and storedata in response to execution of the instructions or software. Forsimplicity, the singular term “processor” or “computer” may be used inthe description of the examples described herein, but in other examplesmultiple processors or computers are used, or a processor or computerincludes multiple processing elements, or multiple types of processingelements, or both. In one example, a hardware component includesmultiple processors, and in another example, a hardware componentincludes a processor and a controller. A hardware component has any oneor more of different processing configurations, examples of whichinclude a single processor, independent processors, parallel processors,single-instruction single-data (SISD) multiprocessing,single-instruction multiple-data (SIMD) multiprocessing,multiple-instruction single-data (MISD) multiprocessing, andmultiple-instruction multiple-data (MIMD) multiprocessing.

The methods illustrated in FIGS. 8-9 that perform the operationsdescribed herein are performed by a processor or a computer as describedabove executing instructions or software to perform the operationsdescribed herein.

Instructions or software to control a processor or computer to implementthe hardware components and perform the methods as described above arewritten as computer programs, code segments, instructions or anycombination thereof, for individually or collectively instructing orconfiguring the processor or computer to operate as a machine orspecial-purpose computer to perform the operations performed by thehardware components and the methods as described above. In one example,the instructions or software include machine code that is directlyexecuted by the processor or computer, such as machine code produced bya compiler. In another example, the instructions or software includehigher-level code that is executed by the processor or computer using aninterpreter. Programmers of ordinary skill in the art can readily writethe instructions or software based on the block diagrams and the flowcharts illustrated in the drawings and the corresponding descriptions inthe specification, which disclose algorithms for performing theoperations performed by the hardware components and the methods asdescribed above.

The instructions or software to control a processor or computer toimplement the hardware components and perform the methods as describedabove, and any associated data, data files, and data structures, arerecorded, stored, or fixed in or on one or more non-transitorycomputer-readable storage media. Examples of a non-transitorycomputer-readable storage medium include read-only memory (ROM),random-access memory (RAM), flash memory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs,CD+RWs, DVD-ROMs, DVD-Rs, DVD+Rs, DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs,BD-Rs, BD-R LTHs, BD-REs, magnetic tapes, floppy disks, magneto-opticaldata storage devices, optical data storage devices, hard disks,solid-state disks, and any device known to one of ordinary skill in theart that is capable of storing the instructions or software and anyassociated data, data files, and data structures in a non-transitorymanner and providing the instructions or software and any associateddata, data files, and data structures to a processor or computer so thatthe processor or computer can execute the instructions. In one example,the instructions or software and any associated data, data files, anddata structures are distributed over network-coupled computer systems sothat the instructions and software and any associated data, data files,and data structures are stored, accessed, and executed in a distributedfashion by the processor or computer.

While this disclosure includes specific examples, it will be apparent toone of ordinary skill in the art that various changes in form anddetails may be made in these examples without departing from the spiritand scope of the claims and their equivalents. The examples describedherein are to be considered in a descriptive sense only, and not forpurposes of limitation. Descriptions of features or aspects in eachexample are to be considered as being applicable to similar features oraspects in other examples. Suitable results may be achieved if thedescribed techniques are performed in a different order, and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner and/or replaced or supplemented by othercomponents or their equivalents. Therefore, the scope of the disclosureis defined not by the detailed description, but by the claims and theirequivalents, and all variations within the scope of the claims and theirequivalents are to be construed as being included in the disclosure.

What is claimed is:
 1. A Computer Aided Diagnosis (CAD) apparatus,comprising: an image receiver configured to sequentially receive images;a region of interest (ROI) acquirer configured to acquire an ROI from acurrent image based on an ROI size transition model; and an ROI outputconfigured to output visual information indicating the acquired ROI. 2.The apparatus of claim 1, wherein the image receiver is furtherconfigured to receive real-time ultrasound images acquired through aprobe in units of frames.
 3. The apparatus of claim 1, wherein the ROIacquirer comprises an ROI detector configured to detect one or more ROIsfrom the current image.
 4. The apparatus of claim 3, wherein the ROIacquirer further comprises an ROI determiner configured to determinewhether a ROI from the one or more detected ROIs is erroneously detectedbased on the ROI size transition model.
 5. The apparatus of claim 4,wherein the ROI determiner is further configured to: determine a sizestate of the detected ROI by matching the size of the detected ROI withthe ROI size transition model; and determine that the detected ROI iserroneously detected, in response to determining that a size state of aprevious image on the ROI size transition model is not capable of beingtransformed to the determined size state of the current image.
 6. Theapparatus of claim 5, wherein the ROI output is further configured tonot output visual information on the detected ROI, in response to thedetected ROI being erroneously detected.
 7. The apparatus of claim 5,wherein the ROI output is further configured to determine the biggestsize state that is possible to transition from the size state of theprevious image using the ROI size transition model, and to output visualinformation on the detected ROI that has a size corresponding to thebiggest size state, in response to the detected ROI being erroneouslydetected.
 8. The apparatus of claim 3, wherein the ROI acquirer furthercomprises an ROI predictor configured to predict an ROI in the currentimage using the ROI size transition model, in response to the ROI notbeing detected from the current image.
 9. The apparatus of claim 8,wherein the ROI predictor is further configured to determine a sizestate transitionable from the size state of the ROI acquired from theimage before the current image using the ROI size transition model, andto predict the ROI in the current image using the determined size state.10. The apparatus of claim 1, wherein the ROI size transition model iscreated using the Markov model learning based on a change in sizes ofROIs in a sequence of images for each interested item, and the ROI sizetransition model comprises size states, a transition possibility betweenthe size states, transition direction, and transition probabilityinformation.
 11. The apparatus of claim 1, wherein in order to indicatea location and size of the ROI in the current image that is output onthe screen, the visual information includes: first informationcomprising at least one of square, round, oval, or cross shapes; andsecond information comprising at least one of color, types of lines, orthickness of lines of the first information.
 12. A Computer AidedDiagnosis (CAD) method, comprising: sequentially receiving images;acquiring a region of interest (ROI), at a processor, from a currentimage based on an ROI size transition model; and outputting visualinformation that indicates the acquired ROI.
 13. The method of claim 12,wherein the acquiring of the ROI comprises detecting one or more ROIfrom the current image.
 14. The method of claim 13, wherein theacquiring of the ROI further comprises determining whether a ROI fromthe one or more detected ROI is erroneously detected based on the ROIsize transition model.
 15. The method of claim 14, wherein thedetermining of the ROI comprises: determining a size state of thedetected ROI by matching the size of the detected ROI with the ROI sizetransition model; and determining that the detected ROI is erroneouslydetected, in response to determining that a size state of a previousimage on the ROI size transition model is not capable of beingtransformed to the determined size state of the current image.
 16. Themethod of claim 15, wherein in response to the detected ROI beingerroneously detected, the outputting of the ROI comprises not outputtingvisual information on the detected ROI.
 17. The method of claim 15,wherein in response to the detected ROI being erroneously detected, theoutputting of the ROI comprises: determining the biggest size state thatis possible to transition from the size state of the previous imageusing the ROI size transition model; and outputting visual informationon the detected ROI that has a size corresponding to the biggest sizestate.
 18. The method of claim 13, wherein the acquiring of the ROIfurther comprises predicting an ROI in the current image using the ROIsize transition model in response to the ROI not being detected from thecurrent image.
 19. The method of claim 18, wherein the predicting of theROI comprises: determining a size state transitionable from the sizestate of the ROI acquired from the image before the current image usingthe ROI size transition model; and predicting the ROI in the currentimage using the determined size state.
 20. The method of claim 12,wherein the ROI size transition model is created using the Markov modellearning based on a change in sizes of ROIs in a sequence of images foreach interested item, and the ROI size transition model comprises sizestates, a transition possibility between the size states, transitiondirection and transition probability information.